#!/usr/bin/env ruby

=begin
Usage: atom-grep [options] regexp [source]
    prints a feed containing every entry in the source feed whose
  text content matches regexp to stdout

    'source' can be a path on the local filesystem, the
  URL of an Atom Collection or '-' for stdin.
=end

require 'atom/tools'
include Atom::Tools

def parse_options
  options = { :regexp_options => 0 }

  opts = OptionParser.new do |opts|
    opts.banner = <<END
Usage: #{$0} [options] regexp [source]
    prints a feed containing every entry in the source feed whose
  text content matches regexp to stdout

    'source' can be a path on the local filesystem, the
  URL of an Atom Collection or '-' for stdin.
END

    opts.on('-c', '--complete', "follow previous and next links in the source feed to obtain the entire logical feed") do
     options[:complete] = true
    end

    opts.on('-v', '--invert-match', 'select only non-matching entries') do
      options[:invert] = true
    end

    opts.on('-i', '--ignore-case', 'ignore case distinctions when matching') do
      options[:regexp_options] |= Regexp::IGNORECASE
    end

    atom_options opts, options
  end

  opts.parse!(ARGV)

  if ARGV.length < 1  or ARGV.length > 2
    puts opts
    exit
  end

  options
end

if __FILE__ == $0
  require 'optparse'

  options = parse_options

  regexp = Regexp.new(ARGV[0], options[:regexp_options])

  source = ARGV[1]
  source ||= '-'

  entries = parse_input source, options

  pred = if options[:invert]
           lambda do |e|
             (e.title =~ regexp) or (e.content.to_s =~ regexp)
           end
         else
           lambda do |e|
             (e.title !~ regexp) and (e.content.to_s !~ regexp)
           end
         end

  entries.reject! &pred

  entries_to_stdout entries
end